Field of the Invention
The invention relates to a technology for a loudspeaker having a plurality of audio signal input systems.
Description of the Background Art
Conventionally, some loudspeakers have a plurality of audio signal input systems. One among those loudspeakers is a loudspeaker to which audio signals for music and the like and signals for warning sounds are input. Such a loudspeaker includes two power amplifiers connected in parallel.
However, when only one of the two power amplifiers connected in parallel outputs the audio signals, an impedance of the other amplifier not outputting audio signals becomes lower. Therefore, large current may flow into the other amplifier. In this case, overcurrent may be generated in the both power amplifiers so that temperature thereof may rise or an electronic part thereof may be damaged.